Dr. Alan Marker receives a letter written in great distress and rides to the crumbling castle of his former university professor, Dr. Eric Usher, to offer his services. He finds the old man caught in the grip of paranoia, his mind eroded by his ongoing attempts to resurrect his comatose daughter Melissa with the blood of abducted women. As he nears inevitable death. Usher enters a twilight world that exists between life and death. There, he is taunted by the blood-drinking ghost of his dead wife, by his faithless housekeeper, and by the various women he has bled to death over the years in the service of his daughter! As the castle begins to crumble in mockery of Usher's moral decay, Harker is forced to flee for his life - but is he too late?